package org.bouncycastle.asn1.icao;

import java.util.Enumeration;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;

/**
 * The LDSSecurityObject object (V1.8).
 *  
 * LDSSecurityObject ::= SEQUENCE {
 *   version                LDSSecurityObjectVersion,
 *   hashAlgorithm          DigestAlgorithmIdentifier,
 *   dataGroupHashValues    SEQUENCE SIZE (2..ub-DataGroups) OF DataHashGroup,
 *   ldsVersionInfo         LDSVersionInfo OPTIONAL
 *   -- if present, version MUST be v1 }
 *
 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier,
 *
 * LDSSecurityObjectVersion :: INTEGER {V0(0)}
 * </pre>
 */
public class LDSSecurityObject
    extends ASN1Object
    implements ICAOObjectIdentifiers
{
    public static final int ub_DataGroups = 16;

    private ASN1Integer version = ASN1Integer.ZERO;
    private AlgorithmIdentifier digestAlgorithmIdentifier;
    private DataGroupHash[] datagroupHash;
    private LDSVersionInfo versionInfo;

    public static LDSSecurityObject getInstance(
        Object obj)
    {
        if (obj instanceof LDSSecurityObject)
        {
            return (LDSSecurityObject)obj;
        }
        else if (obj != null)
        {
            return new LDSSecurityObject(ASN1Sequence.getInstance(obj));
        }

        return null;
    }

    private LDSSecurityObject(
        ASN1Sequence seq)
    {
        if (seq == null || seq.size() == 0)
        {
            throw new IllegalArgumentException("null or empty sequence passed.");
        }

        Enumeration e = seq.getObjects();

        // version
        version = ASN1Integer.getInstance(e.nextElement());
        // digestAlgorithmIdentifier
        digestAlgorithmIdentifier = AlgorithmIdentifier.getInstance(e.nextElement());

        ASN1Sequence datagroupHashSeq = ASN1Sequence.getInstance(e.nextElement());

        if (version.hasValue(1))
        {
            versionInfo = LDSVersionInfo.getInstance(e.nextElement());
        }

        checkDatagroupHashSeqSize(datagroupHashSeq.size());

        datagroupHash = new DataGroupHash[datagroupHashSeq.size()];
        for (int i = 0; i < datagroupHashSeq.size(); i++)
        {
            datagroupHash[i] = DataGroupHash.getInstance(datagroupHashSeq.getObjectAt(i));
        }
    }

    public LDSSecurityObject(
        AlgorithmIdentifier digestAlgorithmIdentifier,
        DataGroupHash[] datagroupHash)
    {
        this.version = ASN1Integer.ZERO;
        this.digestAlgorithmIdentifier = digestAlgorithmIdentifier;
        this.datagroupHash = copy(datagroupHash);

        checkDatagroupHashSeqSize(datagroupHash.length);
    }

    public LDSSecurityObject(
        AlgorithmIdentifier digestAlgorithmIdentifier,
        DataGroupHash[] datagroupHash,
        LDSVersionInfo versionInfo)
    {
        this.version = ASN1Integer.ONE;
        this.digestAlgorithmIdentifier = digestAlgorithmIdentifier;
        this.datagroupHash = copy(datagroupHash);
        this.versionInfo = versionInfo;

        checkDatagroupHashSeqSize(datagroupHash.length);
    }

    private void checkDatagroupHashSeqSize(int size)
    {
        if ((size < 2) || (size > ub_DataGroups))
        {
            throw new IllegalArgumentException("wrong size in DataGroupHashValues : not in (2.." + ub_DataGroups + ")");
        }
    }

    public int getVersion()
    {
        return version.intValueExact();
    }

    public AlgorithmIdentifier getDigestAlgorithmIdentifier()
    {
        return digestAlgorithmIdentifier;
    }

    public DataGroupHash[] getDatagroupHash()
    {
        return copy(datagroupHash);
    }

    public LDSVersionInfo getVersionInfo()
    {
        return versionInfo;
    }

    public ASN1Primitive toASN1Primitive()
    {
        ASN1EncodableVector seq = new ASN1EncodableVector(4);

        seq.add(version);
        seq.add(digestAlgorithmIdentifier);
        seq.add(new DERSequence(datagroupHash));

        if (versionInfo != null)
        {
            seq.add(versionInfo);
        }

        return new DERSequence(seq);
    }

    private DataGroupHash[] copy(DataGroupHash[] dgHash)
    {
        DataGroupHash[] rv = new DataGroupHash[dgHash.length];

        System.arraycopy(dgHash, 0, rv, 0, rv.length);

        return rv;
    }
}
